It is known that fresh food products, both of animal and vegetable origin, are frequently brought to the place of consumption loaded by unsanitary surface substances so as to provide a great risk for the health of the consumer. The unsanitary substances may consist of polluting agents of organic or inorganic chemical and microbic nature, deriving from the environment and animal, such as food residues, soil, secretions, defecations and the like.
In particular, the bacterial contaminations, the amount of which on the surface of live animals (such as swine and chicken) is of the order of several tens millions germs/cm.sup.2 of skin, is responsible for the process of degradation of the food products. The odor characterizing the altering processes of a lot of food products, such as meats, chicken, or poultry, eggs, fish, etc., is mainly due to products deriving from the bacterial metabolism of the microflora (Pseudomonas, Achromobacter, Corynebacteria, etc.) and not to products of the tissue autolysis.
British patent application 2,009,222 published Jun. 13, 1979 in the name of the same applicant as the present application shows one attempt to eliminate unsatisfactory substances. It describes a composition consisting of Tween as a surfactant, sodium bicarbonate as a wetting agent, propyleneglycol as a dispersant, sodium hexametaphosphate as a sequestering agent, urea as an anti-dehydrating agent, citric acid as a buffer agent, sodium silicate and sodium sulfate as the inorganic salts. Clearly the surfactant is different from the present invention because Tween are esters of sorbitol with a fatty acid.
Carboxymethylcellulose is a very useful component because it has recontamination preventing properties but is not present in the composition of this publication.
The composition according to the above British application does not comply with the requirements imposed at present by international sanitary laws with respect to the lack of toxicity of the products being used in contact with the food and the safety of the food products.
The presence of microorganisms and unsanitary substances of chemical nature on the skin and generally on the outer layers of the food products, in addition to limiting the commercial duration of the products, also contributes to a contamination of the underlying muscle tissue in the case of meat and of the comestible inner portions in the case of eggs, by preventing their negotiability since bacteriological requirements must be met.
In the case of vegetables, the surface contamination negatively affects the sanitary and microbiological qualities in all the transformation and preservation steps of the finished products.
The industry in this field has addressed the problem of eliminating these toxic residues and improving the hygienic sanitary degree related to the processing of several food products, by adopting a number of solutions, the main of which is the solution which consists of using disinfectant substances in order to neutralize the bacterial loadings, as disclosed in U.S. Pat. No. 4,140,649 patent.
However, the proposed methods and compositions are practically unsatisfactory. In fact, the unsanitary substances to be removed, particularly in food products of animal origin, correspond to several tens of millions of germs/cm.sup.2 of surface; the problem therefore is that because of the hygienic-sanitary aspect and economical aspect, there is the impossibility of the above mentioned method of removing tens of millions of germs/cm.sup.2 of surface, so that there is a lack of elimination and the food products are rapidly perishable and toxic. Thus, chlorinated water has been already used (containing 10D20 ppm's of active chlorine): however, these disinfection methods lead to the presence of residues of the final products; in the specific case of the slaughtering of swine, it occurs that an amount larger than 50% of chlorine is retained on the meat and particularly on the fat tissue, so as to combine with the lipid fractions thereby providing new products, the dangers of which have not been established.
Moreover, according to the laws, it is not permitted to use disinfectant, antiseptic and antibacterial substances the residues of which would be susceptible to remain for an indefinite time in food products provided for human consumption, with dangerous consequences for the public health. This problem specifically affects the processing or treatment of bird and pork meats, for which the critical steps in which the most contamination occurs are the scalding bath, the plucking and entrails removal steps.
According to conventional meats cleaning methods, the animal carcass is subjected to a first washing step, by immersing it for a precisely set time into a hot water bath (the temperature of the bath being of 52.degree.-55.degree. C.), which also provides the advantage of facilitating the possible subsequent plucking step, in the case of birds, or pile removing step, in the case of swine. The output of the scalding bath, however, that is the total microbic loading on the outer surface of the carcasses corresponds, in the conventional processing methods, to values which can not meet the sanitary rules or requirements, since these values will increase after the plucking, pile removing and entrails removing steps, so as to cause altering processes to occur on the processed meat, to the detriment of their quality and preservation.
A further problem resides in the fact that the organic and inorganic materials carried by the slaughtered animals accumulate in the scalding bath and can achieve a concentration in the case of poultry processing, of 8.56% by weight of the bath itself: in this case, the pollution of meat will depend, in addition to a primitive pollution of the carcasses, on the greatly polluted working environment; in fact, the washing water, will tend to become, in time, a culture broth, mainly if, as it is conventional, one tries to extend the duration to the limit of the eight working hours, as in conventional operations.
The high temperature of the scalding basin is not sufficient to suppress the bacterial flora built-in therein and the most advanced slaughtering technique is not at present suitable to overcome this drawback.
In order to improve the processing sanitary conditions, both of scalding water and of the surface of the food products, the prior art teaches the addition of disinfectant substances to the washing water, which is however prohibited in all countries, in order to reduce the bacterial mass. However, it has been found that the hygienic properties of the slaughtered animal obtained by adding to the bath disinfectant substances, not only continue to be technologically insufficient, but, moreover, the food items are worsened by toxic residues retained on meat up to 60% of the concentration. Under the best hygienic-sanitary conditions and by the most improved technological systems adopted in modern industry, at the end of the processing on meat a bacterial load of the order of 5 10.sup.5 germs/cm.sup.2 of skin is found if simple washing water is used, whereas a bacterial load of about 1-3 10.sup.5 germs/cm.sup.2 of skin is found if to the washing water is added a disinfectant substance, and this is contrary to the CEE's rules. Thus, the bacterial load on the meat surfaces is too great to assure a proper hygienic-sanitary level. In view of the inefficiency or poor results of the above mentioned methods, the above mentioned unsanitary residues remaining on the meat surfaces are considered as technologically unavoidable by those skilled in the art.
Accordingly, there is a need of overcoming the above mentioned technical drawback, by providing a method for cleaning the surface of the above mentioned food products which does not use food additives susceptible to alter their organoleptic properties, aspect and texture, which does not use active disinfectant, anti-bacterial agents or other compositions prohibited by law, which is not toxic, does not alter the food products, and does not leave any residue on the food products itself.
The chemical and bacteriological contamination of the surface of agricultural origin food products is mainly due to the use of fertilizers, pesticide, weed-killer substances, systemic insecticides for plants and animals; these products have revolutionized the agricultural methods, but they leave on the food products residues which make these products incompatible with human health.
Accordingly, it is necessary to remove the above toxic residues also from the surfaces of vegetable origin food products both as they are provided for direct consumption and as they are provided for industrial transformation and processes of preservation.